Under what width must clearance lights be required by state law for trucks or buses?

Clearance lights are critical for ensuring the visibility of trucks and buses, especially during night-time operations or low-light conditions. The requirement for clearance lights is typically established to help other drivers gauge the dimensions of larger vehicles. In most jurisdictions, trucks or buses that have a width greater than 80 inches are mandated by law to be equipped with clearance lights. This regulation aims to enhance safety on the roads by providing additional signals about the overall size of the vehicle, mitigating the risk of accidents caused by visibility issues.

The thresholds represented by the other options do not conform to the commonly enforced standards regarding vehicle clearance. For instance, widths like 50 inches or 70 inches typically apply to smaller vehicles or different classes of regulation, while the requirement for clearance lights kicks in specifically once vehicles exceed 80 inches in width. This distinction serves to ensure that the safety measures are appropriate to the size and operational characteristics of larger trucks and buses.